Annular furnace with revolving hearth for continuous working



May 11 1926.

L. HONIGMANN ANNULAR FURNACE WITH REVOLVING HEARTH FOR CONTINUGUS WORKING Filed May 20, 1924 Fig.1 1 I 1k 1/13 W J i 1 In l yen izafi Patented May 11,

nnrrso stares LUDWIG nonren'ann, or BAD TOLZ, BIoHLnnnor, ,GLEBMANY.

ANNTILAR FURNACE WITH REVOLVING I-IEABTH'FOR CONTINUOUS WORKING.

Application filed. May 20,

especially if they are of large diameter and consequently of comparatively heavy. construction, it is dll'licult tolsolate the furnace space between therevolving hearth and the stationary crown brickwork surrounding the same from the surrounding atmosphere to prevent the escape of heat or gas. F or this reason, furnaces ofthis type had to be heated from below. Such arrangements have the drawbacks thati'the turning gear, for example, the guide rollers, rails and the like serving to support the revolving hearth, are situated within the fire and thus are subjected to considerable wear, and that it is thus difficult to use very high temperatures. The revolving-hearth has therefore to transmit the heat from the heating space to the objects on the hearth and in most cases is for this (reason made of metal, thus causing the heat to be transmitted also to the turning gear which thereby becomes prematurely ruined.

The object of this invention is a revolving hearth furnace for continuous working in which the above described drawbacks are avoided.

This is achieved by movably connecting the revolving hearth with the stationary brickwork of the furnace space surrounding it by means of a liquid or powder seal in such a manner, that a space, isolated from the surrounding atmosphere, is formed,:

whilstpthe turning gear is exposed to said atmosphere. The hearth is preferably formed of a heat insulating material, for example, fireclayr The special construction of the furnace allows the fire clay to be used 1924. Serial No. 714,648.

heating is to be effected, it is advantageous, according to the invention to arrange separate heating spacesin the crown brickwork above the hearth.

.As an alternative, according to the inven tion the furnace space above the hearth may be divided, by means of a horizontal annular plate of heat conducting material, for example, metal, into a reaction space above the hearth and a heating space arranged above said reaction space. i

The metal plate for this reason is preferably thin. if very high temperatures are to be employed there may be some danger of the heated plate sagging. In order to, avoid this, according to the invention, radial ribs may be provided on the metal plate. For example, the annular metal plate may be made of comparatively thin sheet metal on which radial ribs are riveted, for, example, in the form of angle iron. These ribs serve also as heat conducting surfaces.

The new hearth furnace enables. the attainment of any desired high temperature, since an entire, heat insulation in an outward direction is secured and the turning gear members are protected from the heat, this being, for example, necessary in the degasifying of coke with water vapour, especially with low temperature coking in gasworks, in the recovery of ammonia from fuel, in the roasting of ores (production of sulphuric acid), in the manufacture of cement and in calcining (for example; soda process).

Two forms of constructions of an annular furnace with revolving hearth, according to the invention are'illustrated, by way of example, in the accompanying drawings in which Fig. 1 shows a cross-section through the first-form of construction, and

Fig. 2 a plan view of a part thereof, whilst Fig. 3 illustrates a second form of construction in cross-section.

In the form of construction according to Figs, 1 and 2, the rotary annular hearth a is bridged over by the annular crownbrickwork 6, thus forming an annular fur-- nace space 0. The hearth consists of thick refractory plates which may be supported upon an iron structure 03 adapted to run with its rails e on stationary guide rollers f. The structure d is provided with inner and outer annular skirts g which extend vertically downward and engage in annular channels it which are secured to the brick work of the furnace. The channels 72. are filled with a liquid or powdered insulating agent in order to prevent the escape ofheat or gas. In this form of construction heating-channels k are situated in the aIQhed crown of the furnace, which arrangement is preferably employed where the objects to be heated must not come into contact with the heating medium, or where an additional heating by such heating mediumis to be effected. The furnace space 0 forms in such cases a reaction space, into which, for example, when drying objectsare treated upon the hearth,'afn inert gas capable of taking up steam is introduced whilst as a heating agent, or additional heating agent, for example, waste gases may be used in the heating chamlels k. p

The furnace space is provided with charging-device, for example, a charging hopper, and a discharging device, for example, a sweeing bar n and av discharge spout 0. The furnace-space 0 is divided, between the charging and'discharging points by means of apartition p. 'Laterally of the partition p are arrangedthe inlet. and outlet sockets 9,9 for theheating or reaction gases.

Inthe form of construction shown in Fig. 3, the arrangement in general is the same as that in the first example. I The only difference therefrom resides in the fact that the furnace space-between the hearth a and the crown b is divided by means of an annular horizontal thin metal plate 7- into two spaces, of which the lower space 8 directly over the annular hearth, serves as a reaction space and the upper space If! as a heating space. The'metal plate r may be of thin sheet metal and provided with radial reinforcement ribs 1" which may, for example, consist ofangle iron, riveted thereto.

Having now particularly described and ascertained the nature of my said inven' tion andin what manner the same is to be performed "I declare thatwhat I claim is 1. In an annular furnace with revolving annular hearth for continuous working having sealing means between the said hearth and the walls of the annular chamber within which said hearth revolves and having means for heating the material on the hearth andthe walls of the annular chamber within which said hearth revolves and having means -'=for heating thematerial .on the hearth directly, the formation of an additional heating channel above the annular chamber by the division of this chamber by a horizontal annular plate for the purpose set forth.

3. In'an annular furnace with revolving annularhearth for continuous working having sealing means between the said hearth and the walls of the annular chamber within which said hearth revolves and having means for heating the material on the hearth directly, the formation of additional heating .means above the annular chamber by the provision of a conduit for the purpose set forth.

4. In an annular furnace with revolving annular hearth for continuous working having sealing means between the said hearth and the walls of the annular chamber within which said hearth revolves, means for heating the material on the hearth directly and having the furnace space itself divided into two parts by a horizontal annular plate, the provision of the horizontal annular plate withstrengthening and heat radiating members.

5. In an annular furnace with revolving annular hearth for continuous workinghaving sealing means between said hearth and the wall of the amlular chamber within which said hearth revolves, means to heat the material on thehearth directly, a horizontal annular plate to divide the furnace space into two parts, strengthening and heat radiating members formed on the bottom of said plate, and means to heat the material on the hearth indirectly comprising the passage of hot gases through the portion ofsaid chamber above said plate.

In testimony whereof I have signed my name to this specification.

LUDWIG HONIGMAN N. 

